Abdominal exercise apparatus



FIG. 1 is a top view thereof;

FIG. 2 is a bottom view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a side view thereof;

FIG. 6 is the other side view thereof; and,

FIG. 7 is a perspective view thereof.

The broken lines illustrate portions of the abdominal exercise apparatus which form no part of the claimed design. 

The ornamental design for an abdominal exercise apparatus, as shown and described. 